The present invention relates to liquid crystal displays (LCDs) and more particularly relates to LCD heaters and even more particularly relates to systems and controls for LCD heaters.
In the past, LCD heater plates have been incorporated to increase the temperature of the LCD surface. The heater has typically been deposited material such as indium tin oxide (ITO) applied to a glass cover placed adjacent to the liquid crystal layer within the display. Electrical current was then passed through the ITO coating across the display face to generate heat.
While these LCD heaters have enjoyed considerable use in the past, they have several serious drawbacks, especially when used with the new optical compensators with thermal sensitivity. LCDs typically have varied heat dissipation characteristics. The differing rates of cooling of various portions of an LCD display typically result in differing temperatures and a concomitant optical non-uniformity.
Consequently, there exists a need for improved thermal management across the LCD assembly, in order to provide better optical performance of the display.
It is an object of the present invention to provide an improved image for LCDs.
It is a feature of the present invention to include a closed loop LCD heating system.
It is an advantage of the present invention to better manage the temperature gradient existing across an LCD viewing surface.
It is another feature of the present invention to include a plurality of closed loop heating systems, where each closed loop controls the temperature of a display region having a relatively isothermal dissipation characteristic.
It is another advantage of the present invention to provide for more precision in the heating of LCD displays.
The present invention is a method and apparatus for heating an LCD which is designed to satisfy the aforementioned needs, provide the previously stated objects, include the above-listed features, and achieve the already articulated advantages.
Accordingly, the present invention is a method and apparatus providing a plurality of independent closed loop LCD heating systems where each closed loop has associated with it a display region with generally an isothermal heat dissipation characteristic.